Vestibular control of head movements

头部运动的前庭控制

• 批准号: 8059222
• 负责人: Natela M. Shanidze
• 金额: $ 2.59万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8059222
• 关键词: Accounting; Agonist; Animal Behavior; Animal Model; Animals; Attention; Behavior Control; Behavioral; Cavia; Cervical; Clinical; Complex; Conflict (Psychology); Data; Development; Diagnosis; Diagnostic tests; Elements; Equilibrium; Exhibits; Eye; Eye Movements; Functional disorder; Goals; Head; Head Movements; Image; Inferior; Intention; Intervention; Labyrinth; Lead; Measurement; Measures; Medical; Methods; Motion; Motor Neurons; Movement; Muscle; Output; Pattern; Performance; Play; Positioning Attribute; Relative (related person); Research; Retina; Role; Rotation; Signal Transduction; Skeletal muscle structure of neck; Stimulus; System; Testing; Time; Variant; Vision; Visual Acuity; eye velocity; gaze; improved; novel strategies; public health relevance; relating to nervous system; research study; response; tool; vestibulo-ocular reflex

DESCRIPTION (provided by applicant): Eye and head movements must be coordinated to redirect the line of sight ("gaze direction") and to reduce image motion across the retina as the head moves through space. Because these goals are inherently in conflict, the required pattern of coordination is complex. In previous research, eye movements were often used to study vestibular responses (vestibulo-ocular reflex or VOR); experiments were performed in head-restrained subjects undergoing passive rotational stimuli. However, this approach is unable to assess the interplay that naturally occurs between movements of the eye, head, and body and thus is limited in its ability to illuminate the role of the vestibular system in eye-head coordination. In this study, the head is unrestrained and we compare responses to passive whole body rotations (PWBR) and self-generated (active) head movements. PWBR allows for the study of eye and head movements that synergistically contribute to gaze stability. In contrast, during self-generated head movements, compensatory head movements would oppose the animal's intention to redirect the line of sight. Thus, the role of the vestibular system during active head movements must be distinguished from its role during compensatory movements associated with PWBR. The goal of this research is to understand the contribution of the vestibular system during the differing patterns of eye-head coordination provoked by PWBR or self-generated head movements. This goal will be achieved in two specific aims: (1) determine the role of descending vestibular inputs to cervical motoneurons during PWBR and (2) determine the role of descending vestibular inputs to cervical motoneurons during self-generated head movements versus the PWBR condition. Weak galvanic vestibular stimulation (GVS) will be used as an experimental intervention to manipulate the vestibular outflow since this method has been shown to selectively suppress or enhance the vestibular signal from irregular afferents that may preferentially contribute to the vestibulospinal signal. These aims will test the hypothesis that descending vestibular inputs play a significant role in producing the compensatory head movement response during PWBR but may be suppressed during active head movements. Cervical motoneuron activity will be assessed independently of head movement by measuring EMG activity from selected neck muscles involved in the compensatory or active head turns. PUBLIC HEALTH RELEVANCE: Diagnostic tests of inner ear balance mechanisms rely heavily on measurement of eye movements. However, balance is naturally the result of a coordinated interaction of eye, head and body movements; thus consideration of only one of these components may lead to an incomplete understanding of the cause of an inner ear medical problem. This research will be instrumental in the development of novel approaches to clinical tests of inner ear dysfunction as well as its improved treatments.

描述（由申请人提供）：眼睛和头部的运动必须协调一致，以重新引导视线（“注视方向”）并减少头部在空间中移动时穿过视网膜的图像运动。由于这些目标本质上是相互冲突的，因此所需的协调模式很复杂。在之前的研究中，眼球运动经常被用来研究前庭反应（前庭眼反射或VOR）；实验是在接受被动旋转刺激的头部受约束的受试者中进行的。然而，这种方法无法评估眼睛、头部和身体运动之间自然发生的相互作用，因此在阐明前庭系统在眼头协调中的作用方面受到限制。在这项研究中，头部不受限制，我们比较了对被动全身旋转 (PWBR) 和自发（主动）头部运动的反应。 PWBR 允许研究协同有助于凝视稳定性的眼睛和头部运动。相反，在自我产生的头部运动期间，补偿性头部运动会反对动物改变视线方向的意图。因此，前庭系统在主动头部运动期间的作用必须与其在与 PWBR 相关的代偿运动期间的作用区分开来。这项研究的目的是了解前庭系统在 PWBR 或自身产生的头部运动引起的不同眼头协调模式中的贡献。这一目标将通过两个具体目标来实现：(1) 确定 PWBR 期间下降前庭输入对颈部运动神经元的作用；(2) 确定在自生头部运动与 PWBR 条件下，下降前庭输入对颈部运动神经元的作用。弱电前庭刺激 (GVS) 将用作操纵前庭流出的实验干预措施，因为该方法已被证明可以选择性抑制或增强来自不规则传入的前庭信号，这些传入可能优先贡献前庭脊髓信号。这些目标将检验以下假设：下降前庭输入在 PWBR 期间产生补偿性头部运动反应中发挥重要作用，但在主动头部运动期间可能受到抑制。通过测量参与代偿性或主动头部转动的选定颈部肌肉的肌电图活动，可以独立于头部运动来评估颈部运动神经元活动。 公共健康相关性：内耳平衡机制的诊断测试在很大程度上依赖于眼球运动的测量。然而，平衡自然是眼睛、头部和身体运动协调相互作用的结果；因此，仅考虑这些组成部分之一可能会导致对内耳医学问题的原因的不完全理解。这项研究将有助于开发内耳功能障碍临床测试的新方法及其改进的治疗方法。